Temperature-sensitive swelling behavior of polymer gel composed of poly (N,N-dimethylaminoethyl methacrylate) and its copolymers

Polymer gels composed of N,N-dimethylaminoethyl methacrylate (DMAEMA) and a crylamide (AAm) (or ethyl acrylamide (EAAm)) were prepared to observe tempe rature-sensitive swelling behavior. The temperature dependence of equilibri um swelling of poly (DMAEMA-co-AAm) gel was in accordance with the change o f the lower critical solution temperature (LCST) of poly (DMAEMA-co-AAm) aq ueous solution as a function of chemical composition. However, poly (DMAEMA -co-EAAm) gel did not show the similar trend to poly (DMAEMA-co-AAm) gel. I n the case of poly (DMAEMA-co-AAm), the hydrogen bond, which played an impo rtant role in controlling the LCST, was maintained with the formation of th e gel network. However, the hydrogen bond in poly (DMAEMA-co-EAAm) was disr upted significantly with the formation of the gel network. This led to the difference in swelling behavior of polymer gels in response to temperature. (C) 1999 Elsevier Science Ltd. All rights reserved.